BP in Childhood Foretells Adult Hypertension

Children who have even occasional high blood pressure (BP) readings -- as well as overweight and obesity -- are more likely to be diagnosed with hypertension in adulthood, two studies showed.

Having at least one reading in the 95th percentile before leaving high school was, in the first study, associated with a threefold greater likelihood of adult hypertension after adjustment for age, sex, and body mass index (OR 3.1, 95% CI 2.0-4.8), according to Wanzhu Tu, PhD, of Indiana University School of Medicine in Indianapolis.

In the other study, which was based on data from the same cohort, a greater likelihood of being diagnosed with hypertension as an adult was associated with both overweight (OR 2.2, 95% CI 1.3-3.6) and obesity (OR 4.4, 95% CI 2.8-6.9) in childhood, according to Sara Watson, MD, of the Riley Hospital for Children at Indiana University.

Tu's study "emphasizes the need for routine BP [blood pressure] screening in youth and identifies obesity as a risk factor for development of sustained hypertension," she wrote in an email. "Clearly, screening of BP according to NIH guidelines combined with lifestyle modification is needed to prevent adult hypertension."

Added Joshua Samuels, MD, MPH, of the University of Texas Health Science Center at Houston, "Since we teach that hypertension in childhood is defined as sustained readings over the 95th percentile, most primary providers likely dismiss a single elevated reading."

"The study by Tu and colleagues," he wrote in an email, "demonstrates the long-term dangers of even single, isolated blood pressure readings in childhood."

And Watson's study indicates that "physicians should screen for obesity and refer for treatment," Urbina said, adding that "public health measures are needed to address overweight in American youth to prevent a rising incidence of hypertension in the future."

Occasionally High Blood Pressure

Although blood pressure in childhood has been shown to predict adult blood pressure, the clinical significance of only occasional high blood pressure readings in children in terms of adult hypertension risk is unclear.

Tu and colleagues explored the issue using a cohort of 1,117 healthy black and white children (53% female) who were enrolled from Indianapolis schools at an average age of 12.8 in 1986. Blood pressure was measured semiannually until they left high school.

When the participants in the study were an average age of 33.4, they were invited to complete a follow-up assessment. The researchers diagnosed hypertension using direct blood pressure measurements in those who participated and electronic medical records in those who didn't.

At follow-up, there were 119 cases of hypertension identified, mostly from chart review.

The rate of adult hypertension was 8.6% among the participants who didn't have any blood pressure readings at or above the 95th percentile as children, 18% among those with at least one, and 35% among those with at least two.

"Children with even occasional increases in BP should be monitored more closely, and occasional high BP measures should not be dismissed, especially in those with known risk factors such as family history of hypertension, obesity, etc.," Tu wrote in an email to MedPage Today.

"On the other hand, sustained elevation of BP indicates prehypertension or hypertension and may require pharmacological treatment and/or significant lifestyle modification," he wrote. "These kids should be encouraged to exercise regularly, reduce dietary sodium intake, and overweight/obese children should work to lose weight."

Childhood Overweight or Obesity

Tu noted in his study that 59% of the participants who were diagnosed with hypertension as adults were either overweight or obese as children. Watson's study delved deeper into the weight issue in the same cohort of Indianapolis children.

Before leaving high school, 68% of the participants had a normal weight, 16% were overweight (85th to less than the 95th percentile of BMI adjusted for age and sex), and 16% were obese (95th percentile or higher).

The rate of adult hypertension was 6% among those with a normal weight as children, 14% for those who were overweight, and 26% for those who were obese. The differences between the groups held up in a multivariate analysis.

"The findings highlight the importance of preventing and treating overweight and obesity in childhood," Watson wrote in an email. "The current focus is primarily on obese patients. Our findings that those who are overweight are twice as likely to develop hypertension suggest that we should be more aggressive in educating and treating these patients as well."

"It is important," she added, "that we as pediatricians counsel our patients on the risk of hypertension associated with overweight and obesity, and stress that a healthy diet, including reducing salt intake, and exercise may help reduce this risk."

Both Tu's and Watson's studies "highlight that children with risk factors, including children with obesity or even single, isolated high blood pressure, are at an increased risk to develop hypertension at a relatively early age," Samuels said.

"Continued screening of children's blood pressure and earlier intervention, particularly in obese children or in children with elevated readings, might lead to earlier identification of those at most risk," he said. "Targeting intervention to these children most at risk might be the most cost-effective way to avoid serious medical complications in adulthood."

Disclosures

Tu reported being employed by the Regenstrief Institute and receiving a research grant from the National Institutes of Health.

Watson reported receiving a research grant from the National Institute of Diabetes and Digestive and Kidney Diseases. Her co-authors reported receiving research grants from the National Institutes of Health.

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